In order to optimize the posture of the vehicle passenger, more particularly the vehicle driver of a motor vehicle, it is known to make the vehicle seat longitudinally adjustable and the underframe of the seat vertically and incline adjustable and to make the incline of the backrest of the vehicle seat adjustable relative to the seat underframe or seat cushion. For a two or three door vehicle it is further known to make the backrest capable of tipping forward so that the backrest cushion comes to rest on the seat cushion, thus facilitating entry for a rear seat passenger by providing the largest possible entry opening.
In the in use position of the vehicle seat, i.e. in the optimum inclined position of the backrest relative to the seat underframe, the incline adjustment of the backrest can be locked in order to prevent rattling noises and in the event of a crash to prevent the backrest from folding forwards. In order to further improve comfort when climbing into the back of the vehicle, it is also known to lock the forward-folded backrest in a predetermined position in order to prevent the backrest, which is resting with its seat back cushion on the seat cushion, from springing back and thus reducing the access opening.
FIG. 1 shows in a perspective view a vehicle seat 1 without seat cushion and backrest cushion. The seat underframe 2 has on either side of the vehicle seat 1 seat side parts 21, 22 which are connected to a backrest 3 through a common adjusting and tipping axle 4. In order to adjust the backrest incline, a hand wheel 5 connected to an adjusting gear 6 is provided on one side of the vehicle seat 1.
The vehicle seat 1 which is shown in an in use position GS in FIG. 1 can be released from the locked in use position GS by means of an operating handle 30 which is located preferably on the side or top edge of the backrest 3 next to the vehicle door. The operating handle 30 is preferably mounted at the back of the backrest. The vehicle seat can be swivelled about the adjusting and tipping axle 4 into a forward folded position VS in which the backrest 3 can be locked.
FIG. 2 shows a perspective view of an adjusting mechanism according to the prior art for a backrest which can be adjusted in incline and folded over.
The adjusting mechanism consists of a fitting 7 fixed on the seat side part and a fitting 8 fixed on the backrest which can be adjusted in angle relative to the fitting 7 about the adjusting and tipping axle 4. In order to adjust the incline of the fitting 8 fixed on the backrest relative to the fitting 7, there is an adjusting gear 6 which is connected to an angularly displaceable part 9 which has two stops 10, 12 aligned relative to each other. The stop 12 on the angularly adjustable part 9 engages a stop 11, which is mounted on the fitting 8, to establish a set in use position GS of the backrest 3. The stop 10 of the angularly adjustable part 9 secures the in use position GS according to FIG. 1 in connection with a pawl 13 which is sprung in the locking position. Unlocking the in use position GS of the vehicle seat is achieved through an operating element 14 which is guided in a slide guide 15 whereby the pawl 13 can be lifted against spring force.
After releasing the stop 10 of the angularly adjustable part 9 by lifting the pawl 13, the fitting 8 and thus the backrest 3 itself can be tipped forward into the forward folded position VS until the stop 11 of the fitting 8 strikes against the stop 10 of the angularly adjustable part 9. Thus the backrest can only be tipped over in the narrow area which lies between the in use position GS in which the stop 11 of the fitting 8 bears against the stop 12 of the angularly adjustable part 9 and the position in which the stop 11 of the fitting 8 stops against the stop 10 of the angularly adjustable part 9.
If in the in use position GS the incline angle formed between the backrest 3 and seat underframe 2 is very large then it is apparent from the aforesaid illustration that as a result of the restricted tipping angle, when folding the backrest 3 forward into the forward folded position VS, there is still a considerable angle of the backrest 3 remaining relative to the seat underframe 2. Thus, the backrest 3 does not reach the desired forward folded position for an optimal easy entry opening for rear seat passengers. Further, a locking mechanism provided for locking the backrest 3 in the forward folded position VS cannot be activated when the backrest 3 does not reach the desired forward folded position.